During operation the wheels of railroad rolling stock (such as locomotives and railroad cars) become worn. This ear often increases the risk of train derailment and, additionally, may accelerate wheel wear or otherwise adversely affect the running characteristics of the wheels.
These wheels of railroad rolling stock may, with wear, develop flat areas on their circumferences. Such wear often causes a bumpy or vibratory rotation of the worn wheel against the rail. Additionally, such worn wheels may cause derailment of the railway vehicle.
It is thus critical to maintain railway wheelsets to attempt to avoid this condition and, where it occurs, to grind or machine the wheel's circumference so that it is once more perfectly round and concentric with the axial centerline of the wheel and the wheelset. Railway wheelset truing machines are often used for this purpose.
Railway wheelsets may be trued with milling machines, which are adapted to remove metal by feeding a workpiece through the periphery of a rotating circular cutter, such as a milling cutter.
By way of illustration of milling machines suitable for truing railway wheel sets, U.S. Pat. No. 3,540,103 of Oliver Saari (the disclosure of which is hereby incorporated by reference into this specification) discloses a milling cutter for truing wheels of railroad cars and locomotives. The milling cutter of this patent comprises a body of substantially circular cross-section and a plurality of center buttons rigidly associated with the surface of the body, the buttons being arranged in a plurality of spaced ranks to establish a helical array of buttons about the surface of the body, wherein the buttons are spaced within such ranks that buttons which are adjacent in the helical array lie in non-adjacent ranks. A similar cutter is disclosed in U.S. Pat. No. 2,645,003, the disclosure of which is also hereby incorporated by reference into this specification.
The milling cutter of U.S. Pat. No. 3,540,103, and similar prior art milling cutters, are generally disposed vis-a-vis the wheel set to be trued so that the axis of the milling cutter is substantially parallel to the axis of the wheelset during the milling operation, which is often referred to as an "axially parallel circumferential profile milling" process.
Axially parallel circumferential profile milling processes generally require separate profile cutters for each profile shape. Thus, when one must machine different profile shapes, the milling cutter must frequently be changed.
It is an object of this invention to provide a wheelset truing machine which is adapted to true any wheel profile with only one milling cutter.
It is another object of this invention to provide a wheelset truing machine with a high stock removal rate and an improved chip break rate.
It is yet another object of this invention to provide an improved underfloor wheel set truing machine.